Merge pull request #443 from sjrd/scala-3.5

Upgrade to Scala 3.5.0 and support its TASTy format.

build.sbt

@@ -3,7 +3,7 @@ import sbt.internal.util.ManagedLogger
 
 import org.scalajs.jsenv.nodejs.NodeJSEnv
 
-val usedScalaCompiler = "3.4.0"
+val usedScalaCompiler = "3.5.0"
 val usedTastyRelease = usedScalaCompiler
 val scala2Version = "2.13.14"
 
@@ -52,7 +52,7 @@ val strictCompileSettings = Seq(
   scalacOptions ++= Seq(
     "-Xfatal-warnings",
     "-Yexplicit-nulls",
-    "-Ysafe-init",
+    "-Wsafe-init",
     "-source:future",
   ),
 )
@@ -129,7 +129,8 @@ lazy val tastyQuery =
         )
       },
 
-      tastyMiMaPreviousArtifacts := mimaPreviousArtifacts.value,
+      // Temporarily disabled until we have a published version of tasty-query that can handle 3.4.x.
+      //tastyMiMaPreviousArtifacts := mimaPreviousArtifacts.value,
       tastyMiMaConfig ~= { prev =>
         import tastymima.intf._
         prev

tasty-query/shared/src/main/scala/tastyquery/Definitions.scala

@@ -43,6 +43,8 @@ final class Definitions private[tastyquery] (
     scalaPackage.getPackageDeclOrCreate(termName("compiletime"))
   private val scalaCollectionImmutablePackage =
     scalaCollectionPackage.getPackageDeclOrCreate(termName("immutable"))
+  private val scalaQuotedPackage =
+    scalaPackage.getPackageDeclOrCreate(termName("quoted"))
   private val scalaRuntimePackage =
     scalaPackage.getPackageDeclOrCreate(termName("runtime"))
 
@@ -439,6 +441,8 @@ final class Definitions private[tastyquery] (
   lazy val SeqClass = scalaCollectionImmutablePackage.requiredClass("Seq")
   lazy val Function0Class = scalaPackage.requiredClass("Function0")
 
+  private[tastyquery] lazy val ContextFunction1Class = scalaPackage.requiredClass("ContextFunction1")
+
   def FunctionNClass(n: Int): ClassSymbol =
     withRestrictedContext(scalaPackage.findDecl(typeName(s"Function$n")).asClass)
 
@@ -482,6 +486,9 @@ final class Definitions private[tastyquery] (
 
   private[tastyquery] lazy val PolyFunctionClass = scalaPackage.optionalClass("PolyFunction")
 
+  private[tastyquery] lazy val QuotedExprClass = scalaQuotedPackage.requiredClass("Expr")
+  private[tastyquery] lazy val QuotesClass = scalaQuotedPackage.requiredClass("Quotes")
+
   private[tastyquery] def isPolyFunctionSub(tpe: Type)(using Context): Boolean =
     PolyFunctionClass.exists(cls => tpe.baseType(cls).isDefined)
 

tasty-query/shared/src/main/scala/tastyquery/Erasure.scala

@@ -111,6 +111,8 @@ private[tastyquery] object Erasure:
         preErase(tpe.parent, keepUnit)
       case tpe: RecType =>
         preErase(tpe.parent, keepUnit)
+      case tpe: FlexibleType =>
+        preErase(tpe.nonNullableType, keepUnit)
       case _: ByNameType =>
         defn.Function0Class.erasure
       case tpe: RepeatedType =>

tasty-query/shared/src/main/scala/tastyquery/Printers.scala

@@ -77,6 +77,9 @@ private[tastyquery] object Printers:
         print("[")
         printCommaSeparatedList(tpe.args)(print(_))
         print("]")
+      case tpe: FlexibleType =>
+        print(tpe.nonNullableType)
+        print("?")
       case tpe: ByNameType =>
         print("=> ")
         print(tpe.resultType)
@@ -445,6 +448,32 @@ private[tastyquery] object Printers:
           print(c)
           print(">")
         printBlock(bindings, expr)(print(_))
+
+      case Quote(body, bodyType) =>
+        print("'[")
+        print(bodyType)
+        print("]")
+        printBlock(Nil, body)(print(_))
+
+      case Splice(expr, spliceType) =>
+        print("$[")
+        print(spliceType)
+        print("]")
+        printBlock(Nil, expr)(print(_))
+
+      case SplicePattern(pattern, targs, args, spliceType) =>
+        print("$[")
+        print(spliceType)
+        print("]")
+        print(pattern)
+        if targs.nonEmpty then
+          print("[")
+          printCommaSeparatedList(targs)(print(_))
+          print("]")
+        if args.nonEmpty then
+          print("(")
+          printCommaSeparatedList(args)(print(_))
+          print(")")
     end print
 
     def print(caze: CaseDef): Unit =
@@ -577,6 +606,26 @@ private[tastyquery] object Printers:
 
       case ExprPattern(expr) =>
         print(expr)
+
+      case QuotePattern(bindings, body, quotes, patternType) =>
+        print("'<")
+        print(quotes)
+        print(">")
+        body match
+          case Left(termBody) =>
+            print("{ ")
+            for binding <- bindings do
+              print(binding)
+              print("; ")
+            print(termBody)
+            print(" }")
+          case Right(typeBody) =>
+            print("[ ")
+            for binding <- bindings do
+              print(binding)
+              print("; ")
+            print(typeBody)
+            print(" ]")
     end print
 
     def print(tree: TypeTree): Unit = tree match

tasty-query/shared/src/main/scala/tastyquery/Subtyping.scala

@@ -238,6 +238,9 @@ private[tastyquery] object Subtyping:
       isSubType(tp1, tp2.first) || isSubType(tp1, tp2.second)
         || level4(tp1, tp2)
 
+    case tp2: FlexibleType =>
+      isSubType(tp1, tp2.nullableType)
+
     case tp2: ByNameType =>
       tp1 match
         case tp1: ByNameType => isSubType(tp1.resultType, tp2.resultType)
@@ -478,6 +481,9 @@ private[tastyquery] object Subtyping:
     case tp1: RecType =>
       isSubType(tp1.parent, tp2)
 
+    case tp1: FlexibleType =>
+      isSubType(tp1.nonNullableType, tp2)
+
     case tp1: AndType =>
       // TODO Try and simplify first
       isSubType(tp1.first, tp2) || isSubType(tp1.second, tp2)

tasty-query/shared/src/main/scala/tastyquery/Traversers.scala

@@ -120,6 +120,14 @@ object Traversers:
         traverse(expr)
         traverse(caller)
         traverse(bindings)
+      case Quote(body, bodyType) =>
+        traverse(body)
+      case Splice(expr, spliceType) =>
+        traverse(expr)
+      case SplicePattern(pattern, targs, args, spliceType) =>
+        traverse(pattern)
+        traverse(targs)
+        traverse(args)
       case _: ImportIdent | _: Ident | _: This | _: Literal =>
         ()
 
@@ -139,6 +147,10 @@ object Traversers:
         traverse(expr)
       case WildcardPattern(tpe) =>
         ()
+      case QuotePattern(bindings, body, quotes, patternType) =>
+        traverse(bindings)
+        body.fold(traverse(_), traverse(_))
+        traverse(quotes)
 
       // TypeTree-ish
       case TypeIdent(tpe) =>

tasty-query/shared/src/main/scala/tastyquery/Trees.scala

@@ -638,6 +638,33 @@ object Trees {
     override final def withPos(pos: SourcePosition): ExprPattern = ExprPattern(expr)(pos)
   end ExprPattern
 
+  /** A tree representing a quote pattern `'{ type binding1; ...; body }` or `'[ type binding1; ...; body ]`.
+    *
+    * The `bindings` contain the list of quote pattern type variable definitions (`TypeTreeBind`s)
+    * in the order in which they are defined in the source.
+    *
+    * @param bindings
+    *   Type variable definitions
+    * @param body
+    *   Quoted pattern (without type variable definitions):
+    *   `Left(termTree)` for a term quote pattern `'{ ... }` or
+    *   `Right(typeTree)` for a type quote pattern `'[ ... ]`
+    * @param quotes
+    *   A reference to the given `Quotes` instance in scope
+    * @param patternType
+    *   The type of the pattern
+    */
+  final case class QuotePattern(
+    bindings: List[TypeTreeBind],
+    body: Either[TermTree, TypeTree],
+    quotes: TermTree,
+    patternType: Type
+  )(pos: SourcePosition)
+      extends PatternTree(pos) {
+    override def withPos(pos: SourcePosition): QuotePattern =
+      QuotePattern(bindings, body, quotes, patternType)(pos)
+  }
+
   /** Seq(elems)
     *  @param  tpt  The element type of the sequence.
     */
@@ -717,6 +744,65 @@ object Trees {
     override final def withPos(pos: SourcePosition): Inlined = Inlined(expr, caller, bindings)(pos)
   }
 
+  /** A tree representing a quote `'{ body }`.
+    *
+    * @param body
+    *   The tree that was quoted
+    * @param bodyType
+    *   Explicit type of quoted body, which is the source of truth from which we build the type of the quote
+    */
+  final case class Quote(body: TermTree, bodyType: Type)(pos: SourcePosition) extends TermTree(pos) {
+    protected final def calculateType(using Context): TermType =
+      // `Quotes ?=> Expr[bodyType]`
+      defn.ContextFunction1Class.staticRef.appliedTo(
+        List(defn.QuotesClass.staticRef, defn.QuotedExprClass.staticRef.appliedTo(bodyType))
+      )
+    end calculateType
+
+    override final def withPos(pos: SourcePosition): Quote =
+      Quote(body, bodyType)(pos)
+  }
+
+  /** A tree representing a splice `${ expr }`.
+    *
+    * @param expr
+    *   The tree that was spliced
+    */
+  final case class Splice(expr: TermTree, spliceType: Type)(pos: SourcePosition) extends TermTree(pos) {
+    protected final def calculateType(using Context): TermType =
+      spliceType
+
+    override final def withPos(pos: SourcePosition): Splice =
+      Splice(expr, spliceType)(pos)
+  }
+
+  /** A tree representing a pattern splice `${ pattern }`, `$ident` or `$ident(args*)` in a quote pattern.
+    *
+    * Parser will only create `${ pattern }` and `$ident`, hence they will not have args.
+    * While typing, the `$ident(args*)` the args are identified and desugared into a `SplicePattern`
+    * containing them.
+    *
+    * `SplicePattern` can only be contained within a `QuotePattern`.
+    *
+    * @param pattern
+    *   The pattern that was spliced
+    * @param targs
+    *   The type arguments of the splice (the HOAS arguments)
+    * @param args
+    *   The arguments of the splice (the HOAS arguments)
+    * @param spliceType
+    *   The type of the splice, i.e., of this tree
+    */
+  final case class SplicePattern(pattern: PatternTree, targs: List[TypeTree], args: List[TermTree], spliceType: Type)(
+    pos: SourcePosition
+  ) extends TermTree(pos) {
+    protected final def calculateType(using Context): TermType =
+      spliceType
+
+    override final def withPos(pos: SourcePosition): SplicePattern =
+      SplicePattern(pattern, targs, args, spliceType)(pos)
+  }
+
   // --- TypeTrees ------------------------------------------------------------
 
   sealed abstract class TypeArgTree(pos: SourcePosition) extends Tree(pos):

tasty-query/shared/src/main/scala/tastyquery/TypeMaps.scala

@@ -53,6 +53,8 @@ private[tastyquery] object TypeMaps {
       tp.derivedAnnotatedType(underlying, annot)
     protected def derivedMatchType(tp: MatchType, bound: Type, scrutinee: Type, cases: List[MatchTypeCase]): Type =
       tp.derivedMatchType(bound, scrutinee, cases)
+    protected def derivedFlexibleType(tp: FlexibleType, nonNullableType: Type): Type =
+      tp.derivedFlexibleType(nonNullableType)
     protected def derivedByNameType(tp: ByNameType, restpe: Type): Type =
       tp.derivedByNameType(restpe)
     protected def derivedRepeatedType(tp: RepeatedType, elemType: Type): Type =
@@ -123,6 +125,9 @@ private[tastyquery] object TypeMaps {
         case tp: TypeLambda =>
           mapOverLambda(tp)
 
+        case tp: FlexibleType =>
+          derivedFlexibleType(tp, this(tp.nonNullableType))
+
         case tp: ByNameType =>
           derivedByNameType(tp, this(tp.resultType))
 

tasty-query/shared/src/main/scala/tastyquery/TypeOps.scala

@@ -114,6 +114,8 @@ private[tastyquery] object TypeOps:
         apply(z, tp.thistpe)
       case tp: AppliedType =>
         tp.args.foldLeft(apply(z, tp.tycon))(this)
+      case tp: FlexibleType =>
+        apply(z, tp.nonNullableType)
       case tp: ByNameType =>
         apply(z, tp.resultType)
       case tp: RepeatedType =>

tasty-query/shared/src/main/scala/tastyquery/Types.scala

@@ -58,6 +58,7 @@ import tastyquery.Utils.*
   *          +- AppliedType          `C[T1, ..., Tn]`
   *          +- ByNameType            type of a by-name parameter `=> T`
   *          +- ThisType             `C.this`
+  *          +- FlexibleType         `U?`
   *          +- OrType               `A | B`
   *          +- AndType              `A & B`
   *          +- TypeLambda           `[T1, ..., Tn] => R`
@@ -579,7 +580,8 @@ object Types {
           self.superType.typeParams
         case self: AnnotatedType =>
           self.superType.typeParams
-        case _: SingletonType | _: RefinedType | _: ByNameType | _: RepeatedType | _: MatchType | _: RecType =>
+        case _: SingletonType | _: RefinedType | _: FlexibleType | _: ByNameType | _: RepeatedType | _: MatchType |
+            _: RecType =>
           // These types are always proper types
           Nil
         case _: NothingType | _: AnyKindType =>
@@ -1533,6 +1535,22 @@ object Types {
     override def toString(): String = s"AppliedType($tycon, $args)"
   }
 
+  /** A flexible type `T?`, with `T | Null <: T? <: T`. */
+  final class FlexibleType(val nonNullableType: Type) extends TypeProxy {
+    private val myNullableType: Memo[Type] = uninitializedMemo
+
+    final def nullableType(using Context): Type = memoized(myNullableType) {
+      OrType(nonNullableType, defn.NullType)
+    }
+
+    override def underlying(using Context): Type = nonNullableType
+
+    private[tastyquery] final def derivedFlexibleType(nonNullableType: Type): FlexibleType =
+      if nonNullableType eq this.nonNullableType then this else FlexibleType(nonNullableType)
+
+    override def toString(): String = s"FlexibleType($nonNullableType)"
+  }
+
   /** A by-name parameter type of the form `=> T`. */
   final class ByNameType(val resultType: Type) extends TypeProxy {
     override def underlying(using Context): Type = resultType